Fair Value (Schedule Of Key Model Inputs And Assumptions Used To Fair Value Certain Asset-Backed Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	$ 14,904	$ 14,737
Debt Securities, Trading, and Equity Securities, FV-NI	316	106
Other Assets, Fair Value Disclosure	107	95
Assets, Fair Value Disclosure	16,051	15,619
Financial Instruments Sold, Not yet Purchased, at Fair Value	52	85
Other Liabilities, Fair Value Disclosure	107	95
Financial and Nonfinancial Liabilities, Fair Value Disclosure	184	219
Designated as Hedging Instrument [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	9
US Treasury Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	13,599	13,425
Interest Rate Swaps For Customers [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	69	40
Other Liabilities, Fair Value Disclosure	22	36
Fair Value, Inputs, Level 1 [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Assets, Fair Value Disclosure	311	153
Financial and Nonfinancial Liabilities, Fair Value Disclosure	161	182
Fair Value, Inputs, Level 2 [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Assets, Fair Value Disclosure	15,616	15,346
Financial and Nonfinancial Liabilities, Fair Value Disclosure	23	37
Fair Value, Inputs, Level 3 [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Assets, Fair Value Disclosure	124	120
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Foreign Exchange Contract [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	3	4
Other Liabilities, Fair Value Disclosure	2	2
Interest-Only-Strip [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	17	18
Private Equity Funds [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	107	102
Assets, Fair Value Disclosure	0	1
Bank-owned life insurance [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	518	516
Available-for-sale Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	1,283	1,291
Derivative [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	1	1
Other Liabilities, Fair Value Disclosure	1	1
Asset-backed Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	22	21
Fair Value, Inputs, Level 1 [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	40	40
Debt Securities, Trading, and Equity Securities, FV-NI	161	14
Other Assets, Fair Value Disclosure		95
Financial Instruments Sold, Not yet Purchased, at Fair Value	52	85
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	40	40
Fair Value, Inputs, Level 1 [Member] | Private Equity Funds [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Derivative [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	3	4
Other Liabilities, Fair Value Disclosure	2	2
Fair Value, Inputs, Level 2 [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	14,864	14,697
Debt Securities, Trading, and Equity Securities, FV-NI	155	92
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Inputs, Level 2 [Member] | Designated as Hedging Instrument [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	9
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	13,559	13,385
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swaps For Customers [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	69	40
Other Liabilities, Fair Value Disclosure	22	36
Fair Value, Inputs, Level 2 [Member] | Private Equity Funds [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] | Bank-owned life insurance [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	518	516
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	1,283	1,291
Fair Value, Inputs, Level 2 [Member] | Derivative [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Liabilities, Fair Value Disclosure		1
Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	22	21
Fair Value, Inputs, Level 3 [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Interest-Only-Strip [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Assets, Fair Value Disclosure	17	18
Fair Value, Inputs, Level 3 [Member] | Private Equity Funds [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	107	102
Assets, Fair Value Disclosure	0	1
Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Investments, Fair Value Disclosure